Synthesis and properties of TTF vinylogues fused with the 1,3-dithiol-2-ylidene moiety

Several derivatives of 2,2′-ethanediylidenebis(1,3-dithiole) fused with 1,3-dithiol-2-ylidenes (DT-EBDTs) have been prepared. Their cyclic voltammograms consist of three single-electron redox waves. The first redox potential of MeDT-EBDT (+0.37 V vs. SCE in PhCN) is lower by 0.08 V than those of the corresponding TTF, MeDT-TTF. On the other hand, the E2-E1 value (0.13 V) is smaller by 0.18 V than that of MeDT-TTF. The present donors afford semiconducting AsF6− salts, TCNQF4 and DDQ complexes (σrt = 10−5=10−1 S cm−1, Ea = 0.03–0.19 eV).